The  Action  of  Mercaptides  on  Quinones. 


By  John  Langley  Sammis 


. 

- 


4 


■  i.  i  t  i  y 

'•'.'l  ■  I  i."  r 


f  Reprinted  from  The  Journal  of  the  American  Chemical  Society, 
Vol.  XXVII.  No.  9.  September  1905.J 


[Contribution  from  thf  Chemical  Laboratory  of  the  University 

of  Ieeinois.] 

THE  ACTION  OF  MERCAPTIDES  ON  QUINONES. 

By  John  Langley  Sammis. 

Received  July  14,  1905. 

In  a  previous  paper  by  Professor  H.  S.  Grindley  and  the  writer 
upon  this  subject1,  it  was  concluded  that  the  reaction  of  sodium 
mercaptide  on  dichlordiphenoxyquinone  in  dry  ether  consisted  of 
substitutions  and  of  addition  and,  at  that  time,  three  substances 
resulting  from  this  reaction  were  given  the  following  formulas : 

I. 

O 

11 

/c\ 

h5c,s— <y  xc— sc2h5 

II  II 

H5C2S — C  /C-SC2Hs 

ttx.  .  . 

O  J 

Tetrathioethylquinone. 

1  Am.  Chem.J .,  19,  293  (1897). 


THE  ACTION  OF  MERCAPTIDES  ON  QUINONES. 


I  1 2  I 


II. 

H5C2Ox  /S — Na 

>c\ 

H5C2S— cy  xc— SC2H5 

H5C2S— Cx  XC— sc2h5 
Nas/  ^OC2H5 

Addition-product  of  sodium 
mercaptide  and  tetratliio- 
ethylquinone. 


III. 


H5C6OCOs 


>c< 


,SCOC6H5 


H5c2s— c/  \c— sc2h5 


H5C2S— Cx 


>c< 


,C— SC..H 


2  5 


'OCOC6H5 


H5C6OCS/ 

Tetrathioethylquinonediben- 

zoyldithiobenzoylacetal. 


Tetrathioethylquinone,  I,  was  made  from  sodium  mercaptide  and 
dichlordiphenoxyquinone,  by  substitution ;  and  also  from  chloranil 
in  larger  quantity,  though  this  latter  substance  was  not  mentioned 
at  that  time.  vSubstance  II  was  not  isolated  or  analyzed,  but  was 
supposed  to  be  formed  by  addition  when  two  molecules  of  sodium 
mercaptide  were  mixed  with  one  molecule  of  tetrathioethyl¬ 
quinone  in  dry  ether,  or  by  substitution  and  addition  when  six 
molecules  of  sodium  mercaptide  were  mixed  with  one  molecule  of 
chloranil  or  of  dichlordiphenoxyquinone.  Substance  III  was 
made  by  adding  four  molecules  of  benzoyl  chloride  to  substance  II, 
prepared  in  any  of  these  ways.  Substances  II  and  III  were 
considered  to  be  somewhat  analogous  to  the  hemiacetal  derivatives 
described  by  Jackson  and  Grindley.1  The  fact  was  observed  by 
the  authors  of  the  paper  referred  to  (but  not  mentioned  at  that 
time)  that  if  substance  III  was  prepared  from  chloranil,  sodium 
mercaptide,  and  benzoyl  chloride,  then  another  substance  was 
simultaneously  formed,  which,  after  recrvstallizing  from  alcohol, 
proved  to  be  the  dibenzoate  of  tetraehlorhydroquinone  described 
by  Levy  and  Schulz.2  It  is  clear  that  the  formation  of  this  latter 
substance  involves  no  addition,  but  consists  of  reduction  of  the 
chloranil  to  tetraehlorhydroquinone,  which  in  alkaline  solution 
reacts  with  benzoyl  chloride,  forming  the  dibenzoate.  In  view  of 
this,  it  appeared  to  the  writer  to  be  desirable  to  search  for  additional 
facts  to  aid  in  determining  whether  the  action  of  mercaptides 
on  quinones  consists  in  general  of  addition  or  of  reduction  or  of  both. 

In  the  course  of  this  work,  the  method  of  making  tetrathio¬ 
ethylquinone  (Formula  I  above)  was  improved  so  that  95  per 
cent,  of  the  theoretical  yield  can  now  be  obtained,  instead  of  10 
per  cent,  or  less  by  the  former  methods.  It  was  found  that  in  the 

1  Am.  Chem.J.,  17,  577  (1895). 

2  Ann.  Chem.  (Uiebig),  210,  156. 


14816 


1122 


JOHN  LANGEEY  SAMMIS. 


reaction  of  choranil  upon  sodium  mercaptide,  the  substitution 
of  chlorine  proceeds  almost  exclusively,  if  the  substances  be  mixed 
in  water;  while  if  ether  be  used  instead  of  water,  the  reaction 
consists  largely  of  reduction  of  the  quinone  to  the  hydroquinone, 
with  very  little  substitution.  Another  case  was  observed  and  is 
described  below,  in  which  the  use  of  ether  as  a  solvent  caused  the 
formation  of  one  product,  while  if  a  different  solvent  was  used,  a 
totally  different  product  was  obtained.  For  the  preparation  of 
tetrathioethylquinone,  in  large  quantities,  four  molecules  of 
potassium  hydroxide  are  dissolved  in  two  parts  of  water  and 
cooled.  Four  molecules  of  mercaptan  are  mixed  with  an  equal 
volume  of  95  per  cent,  alcohol,  and  after  cooling,  the  solution  is 
added  to  the  potassium  hydroxide,  keeping  the  temperature  below 
200.  The  chloranil  in  the  proportion  of  one  molecule  is  boiled 
with  water  in  a  flask,  in  order  to  thoroughly  wet  the  substance, 
and  is  then  cooled  to  20°.  The  mercaptide  is  now  poured  into  the 
chloranil  and  water,  and  stirred  vigorously.  The  black  solid  mass 
is  filtered  and  washed  on  paper,  until  the  wash- water  comes 
through  neutral  and  colorless,  and  is  then  dried  in  air.  Traces  of 
an  ill-smelling  impurity  are  removed  by  mixing  the  substance  with 
dilute  nitric  acid  (sp.  gr.  1. 10)  to  a  thin  paste,  which  is  to  be  warmed 
on  the  water-bath  for  half  an  hour  or  less,  and  then  filtered,  washed 
with  water  and  recrystallized  once  from  95  per  cent,  alcohol. 
The  yield  is  about  95  per  cent,  of  the  theoretical  quantity.  By 
acidulating  the  first  aqueous  filtrate  a  small  amount  of  tetra- 
chlorhydroquinone  may  be  obtained.  The  molecular  weight  of 
the  substance  was  determined  by  the  boiling-point  method  in 
benzene,  and  was  found  to  accord  with  the  formula  previously 
given. 

Calculated  for  Found,  average  of 

C6(SC2H5)402.  ten  determinations. 

Mol.  wt.  =  348.  352. 

I,EAD  salt  of  tetrathioethyehydroquinone  and  acetic  acid, 

C6(SC2H5)4(OPbOCOCH3)2. 

When  pure  crystallized  tetrathioethylli  ydroquinone  (one  mole¬ 
cule)  is  dissolved  in  95  per  cent,  alcohol  and  treated  with  a  strong 
solution  of  two  molecules  of  lead  acetate  in  alcohol,  a  yellow 
crystalline  precipitate  forms  at  once  in  long  fibrous  needles  at 
low  temperatures,  changing  to  less  bulky  canoe-shaped  crystals 
when  warmed,  or  if  formed  at  a  high  temperature.  The  sub- 


THE  ACTION  OF  MERCAPTIDES  ON  QUINONES.  1 1 23 

stance  was  purified  by  repeated  boiling  with  small  quantities  of 
alcohol  containing  2  per  cent,  acetic  acid,  followed  by  thorough 
washing  on  the  filter  with  hot  alcohol.  Lead  was  determined  by 
suspending  the  substance  in  95  per  cent,  alcohol  and  adding  dilute 
sulphuric  acid,  which  dissolved  the  substance,  but  precipitated 
lead  sulphate  at  once.  This  was  washed  thoroughly  with  alcohol, 
ignited  separately,  heated  wdth  nitric  and  sulphuric  acids  in  the 
crucible,  and  weighed.  Sulphur  was  determined  by  heating  the 
substance  in  a  sealed  tube  with  fuming  nitric  acid  and  a  little 
pure  lead  nitrate  to  260°  for  six  hours.  On  opening  the  tube,  the 
contents  were  evaporated  to  dryness  to  remove  nitric  acid,  w^ater 
was  added,  and  also  some  pure  sodium  bicarbonate.  After  48 
hours,  the  lead  carbonate,  thus  formed,  was  filtered  and  washed, 
and  from  the  filtrate  the  sulphur  was  precipitated  as  barium 
sulphate.  The  lead  carbonate  precipitate  wras  found  to  be  easily 
and  completely  soluble  in  acetic  acid,  which  served  to  show  that  it 
contained  no  lead  sulphate.  The  filtrate  from  the  barium  .sulphate 
was  found  to  contain  no  trace  of  lead,  by  test  with  sulphuretted 
hydrogen. 

Found. 

Calculated  for  , - * - > 

C6(SC2H5)4(OPbOCOCH3)2,  I.  II. 


Lead .  47.0  46.6  47.4 

Sulphur .  14.41  I4-5I  . 


A  portion  of  the  substance  used  for  analysis  on  being  gently 
warmed  with  dilute  sulphuric  acid,  evolved  acetic  acid  vapors. 
The  substance  is  formed  according  to  the  equation : 

2Pb(C2HA)2  +  C6(SC2H5)4(OH)2  =  C6(SC2H5)4  (OPbOCOCH3)2  + 

2hc2h3o2. 

In  one  experiment,  using  14.5  grams  of  lead  acetate,  the  acidity 
of  the  filtrate  was  found  to  be  80  per  cent,  of  the  theory.  The 
substance  is  insoluble  in  water  and  in  all  common  solvents,  but  is 
slightly  soluble  in  boiling  alcohol.  It  is  decomposed  by  glacial 
acetic  acid,  sulphuric,  or  hydrochloric  acids.  Suspended  in 
alcohol  or  ether,  and  treated  with  benzoyl  chloride,  it  forms  lead 
chloride  and  tetrathioethylhydroquinone,  but  no  dibenzoate  of 
tetrathioethylhydroquinone. 

On  account  of  its  insolubility  the  formation  of  this  lead  salt 
serves  as  a  delicate  test  for  the  presence  of  tetrathioethylhydro¬ 
quinone.  When  a  solution  of  lead  acetate  in  alcohol  is  mixed 
with  a  solution  of  tetrathioethylquinone  in  alcohol,  no  apparent 


1124 


JOHN  LANGLEY  SAMMIS. 


change  occurs,  but  if  one  drop  of  sodium  ethylate  solution  is 
added,  a  copious  precipitate  of  this  yellow  lead  salt  appears, 
showing  that  the  reduction  is  immediate.  If  lead  mercaptide  be 
mixed  with  lead  acetate  and  chloranil  in  alcohol,  a  quantity  of  this 
same  yellow  lead  salt  is  formed,  showing  that  the  action  of  lead 
mercaptide  on  chloranil  proceeds  partly  by  substitution  forming 
lead  chloride,  and  partly  by  reduction  of  the  substituted  quinone. 
This  yellow  lead  salt  had  been  obtained  on  various  occasions 
previously,  but  only  after  the  completion  of  the  analyses  reported 
above,  could  any  significance  be  attached  to  its  appearance. 

tetrathioethylhydroquinone  dibenzoate,  C6  (SC2H5)4 

(OCOC6H5)2. 

This  substance  was  made  and  analyzed  in  December,  1896,  but 
was  at  that  time  supposed  to  be  represented  by  the  formula 
C6(SC2H5)4(OCOC6H5)2(SCOC6H5)21  (see  Formula  III  above).  For 
the  purposes  of  this  study  it  was  prepared  again  precisely  as  in 
1896,  and  used  for  a  molecular  weight  determination  by  the 
boiling-point  method  in  benzene. 

Calculated  for  C6(SC2H5)4(OCOC6H5)2)SCOC6H5)2,  mol.  wt.,  832. 

Calculated  for  C6(SC2H5)4(OCOC6H5)2,  mol.  wt.,  558. 

Found:  546,  580,  597,  601,  61  r,  615,  624,  639. 

The  substance  can  be  made  in  various  ways.  It  was  first  made 
by  mixing  sodium  mercaptide  and  C6(SC2II5)402,  and  benzoyl 
chloride  in  ether  as  previously  described.  But  it  can  be  made  with 
equal  ease  if  sodium  ethylate  be  substituted  for  the  sodium 
mercaptide,  and  therefore  it  cannot  contain  more  than  four 
atoms  of  sulphur  in  the  molecule.  It  was  made  in  greater  purity 
and  better  yield  as  follows:  11.5  grams  of  C6(SC2H5)402  were 
dissolved  in  glacial  acetic  acid  and  reduced  by  means  of  zinc  dust 
to  the  colorless  hydroquinone  C6(SC2H5)4(OH)2  as  described  in  the 
earlier  paper.  The  mixture  was  poured  into  water,  stirred, 
filtered,  and  the  mixture  of  zinc  dust  and  precipitated  tetrathio¬ 
ethylhydroquinone  was  washed  with  water  till  neutral.  The 
drained  mixture  was  extracted  with  60  cc.  of  hot  alcohol,  and 
to  the  alcoholic  solution  thus  obtained  was  added  a  solution  of 
1.4  grams  sodium  in  40  cc.  of  absolute  alcohol.  Immediately, 
more  than  half  a  liter  of  ether  was  added,  wdiich  precipitated  a 
solid  mass.  Eight  cc.  of  benzoyl  chloride  were  stirred  in,  and  the 
solid  dissolved.  After  evaporating  the  last  traces  of  ether  and 

1  Am.  Chem.J 19,  293. 


THE  ACTION  OF  MERCAPTIDES  ON  QUINONES.  1 1 25 

alcohol  on  the  water-bath,  the  residue  was  digested  hot  with  10 
per  cent,  aqueous  sodium  carbonate  solution  to  remove  any  excess 
of  benzoyl  chloride.  The  oily  layer  was  filtered  out,  and  washed 
with  water,  when  it  solidified  rapidly.  It  was  washed  with  ether 
to  remove  traces  of  coloring-matter,  and  recrystallized  from  95 
per  cent,  alcohol  in  rhombic  plates,  varying  in  form  somewhat, 
when  crystallized  at  different  temperatures.  The  substance 
having  a  constant  melting-point  at  1310  was  analyzed. 


Calculated  for 

Found. 

/ - * - V 

C6(SC2H5)4(OCOC6H5)2. 

I.  II. 

Carbon . 

.  6o.2I 

60.17  59-94 

Hydrogen .. 

.  5-38 

5-36  5-9° 

Sulphur . 

.  22.95 

23.16  23.07 

Mol.  wt.,  558.  572.1,  531.4,  548.1,  566.8,  584.5;  Average,  560.6. 

Prepared  in  this 

way,  the  substance 

was  found  to  be  identical 

in  properties  with  the  substance  described  in  the  paper  referred  to, 
as  tetrathioethylquinonedibenzoyldithiobenzoylacetal  (formula  III 
above).  The  percentage  compositions  calculated  from  the  two 
formulas  are  almost  identical,  but  the  molecular  weights  differ 
widely. 

Calculated  for  Formula  III,  Calculated  for 

C6(SC2H5)4(OCOC6H5)2(SCOC6H5)2.  C6(SC2H6)4(OCOC6H5)2. 


Carbon .  60.57  60.25 

Hydrogen .  4.81  5.38 

Sulphur .  23.07  22.95 

Mol.  wt. .  832  558 


The  method  of  preparation,  analyses,  molecular  weight  deter¬ 
minations  and  the  chemical  reactions  of  the  substance  show  that 
the  earlier  formula,  III,  is  incorrect,  and  that  the  substance  is 
really  tetrathioethylhydroquinone  dibenzoate. 

It  is  very  easily  soluble  in  ethyl  acetate,  soluble  in  benzene, 
ethyl  alcohol,  or  methyl  alcohol,  nearly  insoluble  in  water,  ligroin 
or  80  per  cent,  alcohol.  It  can  be  recrystallized  from  benzene  or  95 
per  cent,  alcohol.  The  substance  is  decomposed  by  boiling  with 
alcohol  and  sodium  carbonate.  Twenty-five  per  cent,  aqueous 
potassium  hydroxide  attacks  it  very  slowly  at  the  boiling  tem¬ 
perature,  but  if  alcohol  be  added  to  the  mixture,  mercaptan  odors 
are  freely  evolved  and,  in  six  hours,  the  substance  is  entirely 
dissolved.  In  this  respect  it  differs  from  the  dichlordiethoxy- 
quinonedibenzoyldiethylacetal  described  by  Jackson  and  Grindley1 
which  is  stated  to  be  unaffected  by  boiling  alcoholic  soda  solution. 

1  Am.  Chem.J.,  17,  637. 


1126  THE  ACTION  OF  MERCAPTIDES  ON  QUINONES. 

The  effect  of  various  solvents  in  modifying  the  course  of  the 
reactions  has  already  been  referred  to.  Sodium  mercaptide 
acting  on  dichlordiphenoxyquinone  suspended  in  ether,  gave  36 
per  cent,  of  the  theoretical  yield  of  the  substitution-product, 
C6(SC2H5)402.  The  same  materials  mixed  in  water  gave  65  per 
cent,  of  the  same  product. 

When  a  solution  of  sodium  in  alcohol  is  added  to  tetrathioethyl- 
quinone  in  a  little  alcohol,  the  further  addition  of  ether  precipitates 
a  yellow  solid  which  probably  contains  the  sodium  salt  of  tetra- 
thioethylhvdroquinone.  The  subsequent  addition  of  benzoyl 
chloride  dissolves  the  solid,  forming  the  dibenzoate  of  tetrathio- 
ethylhydroquinone,  described  in  this  paper.  But  if  the  same 
process  be  carried  out  omitting  the  ether,  then  benzoyl  chloride 
forms  the  dibenzoate  of  dithioethyldiethoxyhydroquinone. 

dithioethyldiethoxyhydroouinone  dibenzoate,  C6(SC2H5)2 

(OC2H5)2(OCOCsH5)2. 

On  dissolving  two  atoms  of  sodium  in  a  minimum  quantity  of 
absolute  alcohol,  and  adding  the  alcoholate  solution  to  one  mole- 

M 

cule  of  C,(SC2H5)402  moistened  with  a  little  alcohol,  heat  is  evolved, 
the  mass  turns  brown,  and  all  dissolves.  If  the  bulk  of  alcohol 
be  small,  a  granular  crystalline  precipitate  soon  separates  which 
is  easily  soluble  in  alcohol.  On  adding  to  this  mixture  two 
molecules  of  benzoyl  chloride,  much  heat  is  evolved  and  the  solid 
dissolves.  After  removing  alcohol  by  evaporation,  and  the 
excess  of  benzoyl  chloride  by  the  use  of  hot  aqueous  sodium 
carbonate  solution,  the  oily  residue  is  washed  with  water  and  made 
to  crystallize  by  adding  a  little  warm  alcohol.  The  substance  is 
difficultly  soluble  in  95  per  cent,  alcohol,  is  insoluble  in  water, 
ligroin  or  80  per  cent,  alcohol.  It  is  soluble  in  benzene,  chloroform 
or  ether.  It  can  be  recrystallized  from  glacial  acetic  acid,  or 
better  from  ethyl  acetate.  It  forms  equilateral  six-sided  plates 
and  melts  at  184-1 84.5°.  Analysis  gave  the  following  results: 

Found. 

Calculated  for  , - * - . 

C6(SCoH5)2(OCoH5)2(OCOC6H5)2.  I.  II. 


Carbon .  63.87  64.21  64.62 

Hydrogen .  5.70  5.70  5.95 

Sulphur .  12.16  12.45  11.92 

Mol.  wt .  526  587 


The  substance  is  not  affected  by  boiling  with  sulphuric  acid  of 
specific  gravity  1.40. 


THU  ACTION  OF  MERCAPTIDES  ON  QUINONES.  1 1 27 

As  a  result  of  the  work  here  reported,  the  following  conclusions 
have  been  reached : 

(1)  The  action  of  the  mercaptides  of  lead  and  sodium  on  the 
quinones  used  consists  of  substitution  and  of  reduction,  and  no 
addition-products  have  as  yet  been  isolated. 

(2)  The  substance  described  as  an  addition-product  in  the  paper 
referred  to,  under  the  name  tetrathioethylquinonedibenzoyl- 
dithiobenzoylacetal,  does  not  possess  the  formula  there  assigned 
to  it,  but  is  really  the  dibenzoate  of  tetrathioethylhydroquinone,  a 
reduction-product  of  tetrathioethylquinone. 

(3)  It  was  shown  that  the  solvent  used  determines  or  largely 
modifies  the  course  of  several  reactions  between  the  substances 
under  examination. 

(4)  By  the  selection  of  a  suitable  solvent  and  in  other  ways,  the 
method  of  making  tetrathioethylquinone,  was  improved  so  that  95 
per  cent,  of  the  theoretical  yield  can  now  be  obtained  instead  of  10 
per  cent,  or  less  by  the  older  methods. 

(5)  The  preparation,  solubilities  and  analysis  of  the  dibenzoate 
of  tetrathioethylhydroquinone  (m.  p.  1310),  of  the  lead  double 
salt  of  acetic  acid  and  tetrathioethylhydroquinone  and  of  the 
dithioethyldiethoxyhydroquinone  dibenzoate  (m.  p.  184-1 84.5°) 
are  here  described. 

In  conclusion,  I  wish  to  express  my  thanks  to  Professor  H.  S. 
Grindley,  of  the  Department  of  General  Chemistry,  for  permission 
to  undertake  this  work,  in  a  field  of  research  previously  entered 
by  himself. 

University  of  Illinois, 

Urbana,  Illinois. 


